package com.hcc.flow.server.common.utils;

import java.util.HashSet;
import java.util.Random;
import java.util.Set;

/**
 * 邀请码生成器，算法原理：<br/>
 * 1) 获取id: 1127738 <br/>
 * 2) 使用自定义进制转为：gpm6 <br/>
 * 3) 转为字符串，并在后面加'o'字符：gpm6o <br/>
 * 4）在后面随机产生若干个随机数字字符：gpm6o7 <br/>
 * 转为自定义进制后就不会出现o这个字符，然后在后面加个'o'，这样就能确定唯一性。最后在后面产生一些随机字符进行补全。<br/>
 */
public class IIUVUtil {
	/** 自定义进制(0,1没有加入,容易与o,l混淆) */
	private static final char[] r = new char[] { 'Q', 'W', 'E', '8', 'A', 'S',
			'2', 'D', 'Z', 'X', '9', 'C', '7', 'P', '5', 'I', 'K', '3', 'M',
			'J', 'U', 'F', 'R', '4', 'V', 'Y', 'L', 'T', 'N', '6', 'B', 'G',
			'H' };

	/** (不能与自定义进制有重复) */
	private static final char b = 'O';

	/** 进制长度 */
	private static final int binLen = r.length;

	/** 序列最小长度 */
	private static final int s = 8;

	/**
	 * 根据ID生成六位随机码
	 * 
	 * @param id
	 *            ID
	 * @return 随机码
	 */
	public static String toSerialCode(long id) {
		char[] buf = new char[32];
		int charPos = 32;

		while ((id / binLen) > 0) {
			int ind = (int) (id % binLen);
			// System.out.println(num + "-->" + ind);
			buf[--charPos] = r[ind];
			id /= binLen;
		}
		buf[--charPos] = r[(int) (id % binLen)];
		// System.out.println(num + "-->" + num % binLen);
		String str = new String(buf, charPos, (32 - charPos));
		// 不够长度的自动随机补全
		if (str.length() < s) {
			StringBuilder sb = new StringBuilder();
			sb.append(b);
			Random rnd = new Random();
			for (int i = 1; i < s - str.length(); i++) {
				sb.append(r[rnd.nextInt(binLen)]);
			}
			str += sb.toString();
		}
		return str;
	}

	public static long codeToId(String code) {
		char chs[] = code.toCharArray();
		long res = 0L;
		for (int i = 0; i < chs.length; i++) {
			int ind = 0;
			for (int j = 0; j < binLen; j++) {
				if (chs[i] == r[j]) {
					ind = j;
					break;
				}
			}
			if (chs[i] == b) {
				break;
			}
			if (i > 0) {
				res = res * binLen + ind;
			} else {
				res = ind;
			}
			// System.out.println(ind + "-->" + res);
		}
		return res;
	}

	public static void main(String[] args) {
    	/*Map<String, String> map = new HashMap<String, String>();
    	for (int i = 8; i <= 4000; i++) {
    		map.put(toSerialCode(i), toSerialCode(i));
    		System.out.println(toSerialCode(i));
		}
    	System.out.println(map.size());
    	System.out.println(toSerialCode(3602));*/
    	/*String s = "";
    	
    	System.out.println(codeToId("2n6o"));
    	
    	System.out.println(codeToId("8944"));*/
		//System.out.println(toSerialCodeDate());
		//System.out.println(codeToId(toSerialCodeDate()));
		long st=System.currentTimeMillis();
		System.out.println(st);
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < 1000; i++) {
			String c = toSerialCode(st);
			s.add(c);
			System.out.println(c);
		}
		System.out.println("count:"+s.size());
	}
	
	public static String toSerialCodeDate() {
		return toSerialCode(System.currentTimeMillis());
	}
}
